Broadband Power Line Communication is the network operator’s choice for cost efficient smart metering in German smart grid applications. This is due to comparably high data rate and low latency, yielding the possibility to work with state of the art protocols requiring quasi real time transmission of data. However, due to disadvantageous hardware components, such as unshielded power lines, communication in low voltage grids is a difficult task. Consequently, further interferences, for example from household devices, play an important role in terms of availability and quality of service in those communication systems. In this paper, an innovative concept for detecting and measuring the interference of common household devices on the power line communication is presented. The concept consists of two parts identification and recognition as well as rating of interferences, offering the possiblity to draw conclusions about the quality of service in power line communication based smart meter applications by the detection of the load. This concept has been applied for the first time in a field trail on the premises of the Schleswig-Holstein Netz AG in North of Germany. The results are evaluated and presented in this paper.